REGULATORY MATTERS - APC Rate ECR (Details) - Alabama Power $ in Millions	1 Months Ended					12 Months Ended
	Jan. 31, 2023 $ / KWH_Kilowatt_hour	Dec. 31, 2022 USD ($) $ / KWH_Kilowatt_hour	Nov. 30, 2022 $ / KWH_Kilowatt_hour	Aug. 31, 2022 USD ($) $ / KWH_Kilowatt_hour	Jul. 31, 2022 $ / KWH_Kilowatt_hour	Dec. 31, 2022 USD ($) $ / KWH_Kilowatt_hour	Dec. 31, 2020 USD ($) $ / KWH_Kilowatt_hour	Dec. 31, 2019 $ / KWH_Kilowatt_hour	Dec. 31, 2021 USD ($)
Schedule of Regulatory Assets and Liabilities [Line Items]
Current billing rates under rate ECR (usd per KWH) | $ / KWH_Kilowatt_hour		3.510	2.557	2.557	1.960	0.05910	1.960	0.02160
Reduction of over-collected fuel balance							$ 94
Current billing rates under rate ECR, percentage decrease							1.84%
Current billing rates under rate ECR, decrease, amount							$ 103
Current billing rates under rate ECR, amount		$ 500		$ 310
Over (under) recovered fuel cost		(622)				$ (622)			$ 126
Rate RSE refund liability, portion attributable to reduce under recovered balance									$ 126
Other regulatory assets, current
Schedule of Regulatory Assets and Liabilities [Line Items]
Over (under) recovered fuel cost		(102)				(102)
Other regulatory assets, deferred
Schedule of Regulatory Assets and Liabilities [Line Items]
Over (under) recovered fuel cost		$ (520)				$ (520)
Scenario, Forecast
Schedule of Regulatory Assets and Liabilities [Line Items]
Current billing rates under rate ECR (usd per KWH) | $ / KWH_Kilowatt_hour	0.05910